to get access to the apartment you need to have repaired all the projectors on mean street
after doing so you need to talk to gremlin marcus and he will tell you of how he could give you access to a special place for 35 power sparks

once having given the power sparks proceed to the firestation and thin out the balcony revealing a door with the mickey mouse logo on it , once inside youll be greeted by an almost perfect recreation on walts disneyland apartment in the main street firestation

along with the 200 E-tickets you get theres also the concept art
which is walt disneys only drawing he made with oswald and mickey together